Process for the recovery of organic acids and other substances from a tobacco extract



2,204,621 HER mwa DS- AND OT I RACT BGANIC AC TOBACCO EXT Filed July 15, 1938 L. M. RADER OVERY 0F 0 SUBSTANCES FROM A PROCESS FDR THE REC 'June 18, 1940.

Patented .une`18, l194() PROCESS FOR THE RECOVERY F ORGANIC `ACIDS AND OTHER SUBSTANCES FROM `A TOBACCO EXTRACT Lyell M. Rader, deceased,` late of Burlington, N. C., by i Jennie Campbell Rader, administratrix, Burlington, C., assignor to Chemical Extraction Corporation, Elkton, Ky., a corporation of Kentucky Application Julyv 15, 1938, Serial N0. 219,482

1s claims.

The invention relates to the processing of tobacco and more particularly has reference to a process for recovering certain valuable substances and compounds whichhave been extracted there-V from an extract obtained from completely denicotinized tobacco in which any vegetable albumen and pectin therein has been made water insoluble.

Still another Objectis to provide a method foi.

5 from. i recovering citric, malic and oxalic acids in the 5 More specifically the` invention concerns the form of their water soluble salts as well as other` recovery of certain polybasicacids, such as citric, water soluble constituents of the tobacco from a malic and oxalic acids, as well as other constitwater extract obtained from, tobacco which has uents of the tobacco. Heretofore these acids been completely denicotinized` and which has had have been obtained from fruits. Their cost has the albuminous matter and pectin therein ren 10 been relatively high due to the complicated exdered Water insoluble. i traction procedure, low extraction and recovery A further object of the invention isto coagulate yield, the fact that only a very `low percentage of the albuminous material and the pectin and to the juices of the fruit, from which they'are exremove the same by high speed centrifugal sep- 1 tracted, can be used, and also the fact that culls` aration' to permit the recovery of Water soluble 16 are employed rather than choice or eating fruit, salts of organic acids and other soluble constitit being commercially impractical to use the latuents of tobacco contained in a water extract obi ter. Moreover undesirable acetic acid is obtained tained from denicotinized tobacco, the albuminwith the polybesio acids on their extraction. ous matter and pectin beine in insoluble form.

` As is known citric, malic, and oxalic acids are Yet a further object of the invention is t0 prO- 20 constituents of tobacco. However, their extrac- Vide` a process for the recover-y of citric, malic tion is most diicult ii not impossible due to the and oxalic acids, certain alkalies, ammonia compresence in the' tobacco` of nicotine, albuminous peurlds, DhOSDhateSaHd nitfogeneus H12-tte? from material including vegetable albumin, and also a water extract, also containing water insoluble .some form of pectin. This di-culty may be overalbuminous matter and pectin, Obtained lOmde- 25 come if the nicotine is first entirely extracted nicotlnized tobacco wherein the albuminousimatfrom the tobacco, the acids mentioned convertedy tei' and Dect/indre IemOVed by high Speed Centrifinto their water soluble salts and through suitable usal separation, the 'acids recovered as a precipi processing the albuminous matter and pectin itate of their calcium salts by the addition of rendered water insoluble. The salts aswellas the reagents tothe extract and the other constituents 30 remaining valuable constituents of the tobacco reeel/'ered asa Still deposit Obtained 0H distfilli`` are removed in a `water extract along with the tion of the remaining extract or mother liquor to albuminous matter and the pectin, the tobacco J recover the reagent in the same for reuse in the on the removal of the extract beingleft in, the; DlOCes-sform` of cellulose. With these and other objects in View the inven 35 A5 will hereinafter appear his invention pron tion consists in the method to be hereinafter set vides a simple and highly eflicient and hence inforth and claimed with the understanding that expensive process for recovering the organic acid the steps thereof, the apparatus deseribed fOr salts and the other compounds and substances of Carryingthem Out andthe feataltsllsed es Well 40 value from the water extract while ridding the astheir'quantities may be `Widely Varied by thOSe 40 same of the vegetable albumen and the pectin skilled in the art without departing flOm the which though water insoluble prevents theV em- `spirit of the invention or thel scope 0f the apployment of ordinary recoverymethods. pended claims.

It is hence the major object of this invention Briefly the invention Comprehends the recov- 'to provide a novel, inexpensive and eflicient procery 0f Oitlie, maiiC, and OXalie acids, alkalies,` 45 ess for recovering certain of the valuableconstitammonia compOiiIldS and `IiitIOEeIlOlls matter uents extracted from tobacco. from a tobacco extract. One method of practi- An equally important object of the invention cally @fleeting this @Oneept is; t0 eeOVer these is the provision of a method for recovering, from Constituents of tobacco `from a" water extract oban extract obtained by processingtobacco, ortained from tobacco Which has been denicotinized' 50 ganic acids and other tobacco constituentsdisand `which has had the vegetable albumen and` solved inthe extract while freeing the latter of` pectin therein rendered water insoluble. albuminous material and pectin. The invention includes removing, from` this Another object of his invention is toprovidea* extract in which the acids are present in the'form` 55. process for `rebovering salts of polybasic acids of their dissolvedammonia" salts and in which` 55.

plished by precipitating themalltogether as calcium salts of the acids by the addition of calcium chloride and alcohol to the extract or they may be recovered separately. The latter may be carried out by adding only the calcium chloride to the extract and through suitable processing including cooling, agitating and heating of the extract obtaining separate precipitates of calcium oxalate-and, calcium citrate. After separation of theseoxalatand citrate salts from the mother' liquor,y calcium malate is precipitated by adding alcohol to the extract and is removed therefrom.

\ Where the calcium salts of the acids are precipitated vtogether they are separated yfrom each other. No matter how obtained the separate salts are subjected torening and recrystallization for conversion into their acids. i l

After recovery of the acid salts there still. remains in the-mother liquorV the other previously described tobacco constituents and also alcohol used in the process. To recover the alcohol for reuse the extract is distilled and the alcohol thus obtainedV sent to a storage tank. This procedure results inthe leaving of a still deposit which contains the lalkalies, ammonia compounds, phosphates andnitrogenous matter. If desired, this deposit may be mixed with the tobacco which. has been reduced to cellulose and from Which it vhas bcenextracted to provide a fertilizer or any other use may be made of the deposit.

v In order to make his invention more clearly understood I `have shown in the accompanying drawing, means for carrying the same into practical elfect without limiting the .improvements in their useful application to the particular constructions which, for the purpose of explanation have beenmade the subjectof illustration.

In thedrawing the figure shows a now sheetl for a. plant designed to carry out the process o this` invention. i v `Throughout the drawing similar reference numerals refer to like parts and elements shown on the iloW sheet. g i i As herein pointed o ut the invention relates to a process for the recovery of all of the valuable orfganic and inorganic constituents dissolved in a vwater extract obtained in the treatment of com,-

In his application above referred to he has Vshown as a final product an oil free tobacco from whichrthe entire nicotine .and chlorophyll content has been extracted. There remains in this tobacco ammonia salts of oxalic, citric and malic acids, (due to the use of ammonia in displacing the nicotine and chlorophyll of the tobacco in the- PTQCQSS Qf m5. @wending appaton) QgethQll ;bacco constituents from a Water extract. This may be accomplished by following the Lyford l process and obtaining, the tobacco values as solutes' in a` water extract in which the albuminous matter and pectin are present in insoluble form.

In accordance Iwith the Lyford process denicotinized tobacco is placed in an extractor and subjected to heat treatment as for example by live steam Which is allowed to condense to boiling water` and to which may be added boiling water or boiling water may be used alone. All of this time the tobacco is undergoing violent agitation, which-continues for some time. The effect of this treatmentis to render the albuminous matter and pectin Water insoluble and to float it olf from the tobacco. At the same time the valuable constituents which it is desired to extract from the tobacco are dissolved by the Water. It is here that the processvforming the subject of this invention begins, namely the recovery ofthe substances already named from this extract or mother liquor.

vAs shown in the drawing, in carrying out his invention, tobacco, from which nicotine and chlorophyll has been removed in accordance with the practice disclosed in his previously mentioned co'pending application, is loaded intothe receiving bin'l from which it is emptied into one or gmore extractors 2. A hot Water line 3 connects the extractor or extractors with a hot Water tank 4 which is `suitably heated as shown. Also a steam line (not shown) may be run to the extractors. i

'Ihe type of extractor used is such that the tobacco contained` therein may be subjected to extremely violent4 agitation. This is begun as soon as the mechanism is loaded and then boiling water isintroduced into the extractor. Agitation of the tobacco continues for a time sufficient to cause all ofthe constituents of the tobacco which it isdesiredto extract therefrom to go into solution or to be taken up by the water. As a result of this treatment and the prior nicotine and chlorophyll removal the tobacco is reduced to cel lulose.

He has discovered that for extraction purposes boiling Water alone worksy most satisfactorily.

Also he has found that its amount may be determined by the nicotine content of the tobacco before complete,denicotinization For example in processing any Kentucky tobacco, whichwill average a 4% lnicotine content, 3 pounds of water per pound of tobacco is used to obtain the extract.- 'Ihe quantity or volume of boiling Water employed will be less for a tobacco of a lower 4nicotine content `and will be greater than that described for a tobacco with an original nicotine content well over 4%. Y

After this treatment the tobacco and the mother liquor are ready `for further processing to recover the desired chemical values in the extract. To accomplish this theentire contents, tobacco and water, of the extractor or extractors 2 are removed therefrom and by `means of-conveyor 5 'and elevator 6 are introduced into a storage bin 1 from whence they are feed into a centrifuge 8Where as much of the Water as is possible is cenirifused off ,fromthertqbaccol Thisliquor obtained from centrifuging is taken through line 9 to the receiving tank I from whence it is pumped through the line I I into a surge tank I2 and then allowed to enter a centrifugal separator or clarifier I3 from which it is sent to a liquor storage tank I4. l

Despite centrifuging, which is done at very high speed, there still remains in the tobacco mass some of the extract or liquor containing the ma terials which it is desired to recover. To remove this so called center water, the tobacco mass in the centrifuge has added thereto 1 pound of clean boiling Water per pound of tobacco. (The amount of the wash water is based on that needed for tobacco with an original nicotine content of L1%.) This water Washes out any remaining original water which may still be in the tobacco; After centrifuging the wash water is sent to the liquor storage tank, in the manner previously described, and is added to the mother liquor therein, If desired the original extract obtained in initial centrifuging may be held in the receiving tank I0 and the wash water added to it there after which the mixture, which will hereinafter be referred to as the mother liquor or extract, is then passed to the storage tank `III as already outlined. l

While he has described how-a water extract having in solution all the valuable constituents remaining in tobacco after the extraction of nicotine and chlorophyll` may be obtained, it should be `kept in mind that this extract contains albuminous matter and pectin, the presence l of which, although in insoluble form, prevents recovery of the substances and compounds it is desired to recover. Hence it is essential that these unwanted substances be removed so that `the solutes of the extract may be recovered.

Experience has shown that they cannot be removed by filtration for the reason that the albuminous matter and the pectin will clog any type of lter now in use. It has been discovered, however,` that they` may be removed from the mother liquor or extract by centrifugal separation at extremely high speeds. Frequent resort must, however, be made to this separation means due to the tenacious tendency these substances have for remaining in the mother liquor. To this end use is made of progressive high speed cen-,- trifugal separation as the recovery process advances so that the albuminous material and pectin will at least be reduced to :such an infinitesimal quantity, if not entirely removed, as to allow the unhindered recovery ofV the desired compounds and substances. Ihe centrifugal separation also effectively removes any other insoluble tobacco constituents which may be contained in the extract.

All of the centrifugals described or to be hereinafter described for use with the process, as for example the centrifuge and clariers, have their rotating separator elements driven at a per-ipheral speed of from 9,000 to 10,000v feet per minute. Very satisfactory results have been obtained with the speeds just given. Higher speeds may be used where the mechanical construction of the l are driven.

From the foregoing description it will be appreciated that some pectin and vegetablealbumen are removed from the extractl in the centrifuging and washing step of the process in which occurs the centrifuge 8. It should be noted however that this centrifuging also has the additional function` of literally wringing the tobacco dry or in other words, removing all of the extract by having 75% of its volume evaporated olf, the

vapors being taken off in any well known, manner and the `concentrate being removed from the evaporator through pipe line I'Ia,` to the hot liquor storage tank I'I. The effects of the evaporation treatment is to concentrate the mother liquor into a smaller volume which facilitates the recovery of the tobacco constituents therein. Also excess or freeammonia in the extract, resulting from the use of such gas in denicotinizing the tobacco, is removed.

To assist in the removal of albuminous matter and pectin, which remains in the mother liquor as it comes from the storage tank I4, a sufficient quantity of a neutral astringent is added thereto for the purpose of coagulating these substances. Suitable astringents include alum, iron chloride and sumac. The astringent may be added either prior to `or during evaporation of the mother liquor. As shown in the drawing the astringent from a reservoir I9 is passed through pipe line 2D and by means of the pump 20a is forced into the evaporators as the mother liquor undergoes evaporation. This means of coagulating the a1- buminous material and the pectin has proved very satisfactory.

From the hot liquor tank the mother liquor, now concentrated to 25% of its original volume, is sent through a clarifier I8 and from there to the rst precipitate tank 2|. I8 which is of the high speed type centrifugal separation of albuminous material and pectin from the extract again takes place. This separation in the majority of instances removes all of the albuminous material and pectin left in y' `the mother liquor after the treatment already described. In any event such iniinitesimal traces of these substances are left in the extract after it has passed through the clarifier I8 that recovery of those substances which it is desired to obtain for commercial use may be effectively proceeded with, this latter beginning in the precipitate tank 2l. Also any other insoluble matter remaining inthe extract is removed.

Recovery of the organic acids in the forml of their salts is now begun in the precipitate tank 2|. To assist in such recovery, the tank is provided with a cooling coil 22 `for cooling the hot liquor as it comes from the hot liquor tank I'I and clarierl and also witha blade agitator 23. The recovery of the salts of the citric, malic and oxalic acids may be accomplished by precipitating these salts simultaneously or separately. Either practice results in a like yield of these substances but from acommercial standpoint it is preferred to precipitate them separately.

In the l recovery as separate precipitates it should be noted that the mother liquor comes into the precipitate tank ZI at a very high temperature. It is now cooled down at least to 70 F.

In the `clariier through the operation o'f the' cooling coil 22. A precipitant which will, under proper conditions, cause the precipitation of all the 4acid salts is now added to the cooled liquor. Such a precipitant is calcium chloride which is introduced into the cooled liquor from the storage tank 21a, in a volume slightly in excessof the theoretical amount needed to satisfy and precipitate all of the acid salts in the mother liquor. This required volume is readily determined since from analysis of the tobacco prior to any processing its acid content for the acids being recovered is known.

The result of the addition ofthe calcium chloride is to immediately precipitate the salt of the o-xalic acid as calcium oxalate.

It has been pointed out that in denicotinizing the tobacco gaseousammonia has been employed. This ammonia frees the nicotine and co-mbines with the organic acids present in the tobacco to form ammonia salts of these acids. What now happens, when the calcium chloride is added to the mother liquor, is metathesis. That is the calciumof the calcium chloride replaces the ammonia in the ammonia acid salts and converts them into calcium salts of citric, malic and oxalic acids. These calcium salts, under proper conditions, are easily and readily precipitated from the mother liquor. .In fact as already noted the calcium oxalate is precipitated from the cooled liquor immediately on the addition of the precipitant.

After the formation of the calcium oxalata this precipitate and the mother liquid are passed through line 24, to a clarifier 25 where the oxalate is removed by centrifugal separation and taken off through line 26 while the mother liquor is sent through line 2l to a second precipitate tank 28 for recovery of the calcium citrate contained therein. Y

Further treatment ofthe precipitated calcium oxalate is necessary to renne it and convert it into its acid. This includes the addition of the usual reagents to the oxalate to free the calcium, ltration, and crystallization, by evaporation and drying, to obtain the acid.

The mother liquor in the precipitate tank 28 now contains calcium salts of citric and malic acids. As already mentioned, under proper conditions the citric salt may be precipitated. For this purpose the precipitate tank is provided With a steam coil 29, connected to a suitable steam source. The coil is operated until the temperature of the mother liquor is raised to 212 F. and is held at that temperature for a short time, usually about a minute. This procedure results in the precipitation of calcium citrate. After formation of the precipitate the entire contents of the precipitate tank 28 are passed through line 30 to a high speed clarifier 3|. In the clarifier the mother liquor and precipitate are centrifugally separated, the former being sent by line 33 to a third precipitate tank 34. While the precipitate of calcium citrate is drawn off as indicated at 32. On removal from the clarier 3| the calcium citrate is rened in a manner similar to that described'in connection with the treatment of the calcium oxalate so as to convert it into citric acid.

Alcohol is used to obtain the calcium malate in the mother liquor. TWO Volumes of alcohol per volume of liquor in the `tank 34 are introduced therein by Way `of pipe lines 35 and 36. Agitation of the liquor by agitator 38 effects precipitation of calcium malate. After precipitation of the malate the mother liquor, noW` containing only alcohol and certain tobacco'values, is drawn off from the precipitate tank for further treatment While the calcium malate is removed therefrom for rening and conversion into malic acid by means similar to those already outlined for the other acid salts.

If calcium `chloride and alcohol, in the volumes mentioned, are simultaneously added to the mother liquor in the tank 2l While the liquor is agitated with agitator 23y the calcium salts of the organic acids will be precipitated in mass. This is the second recovery practice. After precipitation the liquor is drawn off into the dilute alcohol tank 43 for further processing, While each of the salts are separated from the precipitate and is refined and converted into its acid by methods like those already described. f I

While certain Volumes or quantities of reagents have been specified it should be noted that use of greater quantities of .calciumchloride and alcohol Will not affect the practice of the process'.

The acids and their salts are recovered in an exceptionally pure state. They are entirely free of objectionable acetic acid and salts thereof Whilel each separate precipitate is obtained free of the salts of the other acids it is desired to recover. Even in pilot or test plant operations, which are'of course rough and approximate at best, this has been` true in nearly all runs.

`This-.present process, is a link in` a chain of processes designed to extract all of the constituents of the tobacco plant and to recover the valuable ones for commercial use While reducing the tobacco to cellulose. Actually the recovery process herein described is part of a Whole, the products obtained by its practice being by-products `from the main extraction and recovery of nicotine from the plant. Most valuable of these are the citric, malic and oxalic acids. While the content-of some. of these organic acids in the tobacco is `relatively small, it Will Vbe appreciated that Where a high extraction` yield, is coupled with a high recovery yield it is commercially practical to recover these acid values after the extraction and recovery of the nicotine and chlorophyll. As previouslyoutlined in recovering each acid from'its calcium salt, the calcium is precipitated and removed by filtration While the remaining solution is concentrated to crystallize the acid contained therein. For the first tobacco batch processed this gives a comparatively low acid recovery yield. However, Where the concentrated acid solution of the first run is added to that of the next succeeding run and this practice is continued for several runs a high recovery yield for each acid may be procured. Through such procedure recovery yields for-citric, oxalic and malic acids of consistently over 94% of the total content of each of these acids in the tobacco plant have been obtained. To bear this out is the fact that laboratory control samples of extracts made up of pure chemicals and processed in accordance with the method herein outlined have shown a recovery yield average for all the desired acids of 98.8% and individual acid recovery yields of over 99% for each of thedesired acids.

It has been previously pointed out that the process of this invention is one of a chain designed to extract and recover all of the valuable and useful constituents of tobacco. What might be referred to as a -by-product of the main acid recovery herein described or as a sub by-product of the chain of processes, is the recovery from the mother. liquor of .thetobaccochemical values '(5 `which remain after separation therefrom yof the These include ammonia, po-v organic acidsalts. tassium, sodium and calcium alkalies, other ammonia compounds, phosphates and nitrogenous matter. Also themotor liquir contains alcohol, remaining from the separation of the malic acid eisalt, Whichit is desired to recover for reuse in `into the dilute alcohol tank 43 and from there is pumped through line 44 into the still.

Distillation is begun with the mother liquor in the still. The alcohol is recovered in the recovery tank 45 and is pumped through line t6 to the storage tank 3l for reuse While the remaining tobacco `constituents are removed from the still in the form of a crude still deposit. Suitable means, not shown, may be provided for supplying the alcohol storage tank with fresh alcohol to compensate for mechanical or operating losses.

It Will be appreciated that the` tobacco `con- "stituents noted as being present in the still deposit are good fertilizing materials.

This deposit may be used to form a fertilizer mixture by adding it to or incorporating it with the cellulose remaining after its extraction from Vthe denicol tinized tobaccoL Of course it will be well' undere stood by those skilled in the art that the use of maining in the mother liquor after the extraction, separation and recoveryof `the substances herein described, its recovery yield is best considered in pounds. In the treatment of Kentucky tobacco or tobacco With a nicotine content of about 4% this yield will average around 20 "pounds of still deposit per 100 pounds of tobacco.

From the foregoing it will be appreciated that he has provided a simple, highly efficient, and hence inexpensively practiced process for recovlering organic acids and other compounds from a tobacco extract obtained from denicotinized tobacco. It Willjalso be realized that he has provided a process, which byfreeing the tobacco extract from substances Whose presence would prevent recovery of the desired tobacco constitutents, allows the completion of a chain of processes working to thepractical commercial extraction and recovery of all of the valuable constituents of tobacco.

While I have shown and described the preferred embodiment of his invention, I Wish it to be understood that the invention is not conned to the speciiic method steps, reactants, and details of construction for carrying out the process herein set forth, by Way of illustration, as it is apparent that many changes and variations may be made therein, by those skilled in the art, Without departing from the spiritof the invention, or exceeding the scope of the appended claims.

What is claimed is:

1. In a process for recovering polybasic acids and other valuable tobacco constituents contained as solutes ina water extract obtained from denicotinized tobacco, the acids being present in the form 'of their salts,` the extract also `containing insoluble material including ialbuminous matter arid'pectin, the steps of subjecting the extractto high speed centrifugal separation, `evaporating the extract to concentrate it and reduce its volume, again subjecting the extract to high speed centrifugal separation, adding calcium chloride and alcohol to the extract `to precipitate the salts of` the polybasic acids asy calcium salts of the same, recovering the salts from the extract by high speed centrifugal separation and converting them into their acids. i

2. In a process for recoveringl polybasic acids and other valuable tobacco constituents contained as solutes in awater extract obtained from denicotinized tobacco, the acids being present in the form of `their salts,jthe extract also containing insoluble material including albuminous matter and pectin, the steps of subjecting the extract to high speed `centrifugal separation, evaporating the extract to concentrate itandvreduce its volume While adding a neutral astringent thereto, again subjecting theextract to highspeed centrifugal separation, adding calciumchloride and alcohol to the extract to precipitate the salts of the polybasic acidsas` calcium salts of the same, recovering the salts from the extract byhigh speed centrifugal separation and converting `them into their acids. i l

3. Inl a process for recovering polybasicacids and` other `valuable tobacco` constituentsfcontained as solutes in a VWater extract obtained from `denicotinized tobacco, the acids being present inthe form of their salts, the extract also containing insoluble. material `including albuminous matter and pectin, `the steps of subjecting the extract to` high Vspeed centrifugal `separation, evaporating the extract to concentrate it and reduce its volume While adding an astringent thereto from theclass consisting of alum',

`iron chloride `and surnac, againsubjecting the extract to high speed centrifugal separation, adding `calcium chloride and alcohol to the extract to precipitate the salts `of the polybasic acids as calcium salts of the same, recovering thefsa'lts from the extract by high speed centrifugal sepa-` ration and converting them into their acids.

4. In a process for recovering the organic acids and other valuable constituents 'of tobacco present as solutes in an extractobtained from denicotinized tobacco, albuminous matter and pectin being present in the extract as insoluble material, the steps of removing the albuminous matter andpectin by subjectingtheV extract tov successive stages ofhigh speed centrifugal separation, precipitating `the acids in a` form of their salts and separating the precipitates from` the extract.

5. In a process for recovering the organic acids and other valuable constituents of tobacco present as solutes in an extract obtained from denicotinized tobacco, albuminous matter and pectin being present in the extract as insoluble material, the steps of removing said albuminous matter and pectin by subjecting Ithe extract to successive stages of high speed centrifugal separation,eprecipitating the acids in the form of their salts, and separating the precipitates from the extract, the albuminous matter and pectin being coagulated prior to the stage of centrifugal separation preceding precipitation of said salts.

6.` In a process for recovering the organic acids and other valuable constituents of tobacco present as solutes in an extract obtained from denicotinized tobacco, albuminous matter and pectin being present inthe extract as insoluble material, the steps of removing said albuminous m'attter and pectin by subjecting the extract to successive stages of high speed centrifugal separation,precipitating the acids in a formof their salts, and separating the precipitates from the extract, the albuminous matter and `pectin being coagulated by adding a neutral astringent to the extract prior to the stage of centrifugal separation preceding precipitation of said salts.

7. In a processfor recovering the organic acids and other valuable constituents of tobacco present as-solutes in an extract obtained from'denicotinized tobacco, albuminous matter and pectin being present in the extract as insoluble material, the steps of removing the albuminous matter and pectin by subjecting the extract to successive stages of high speed centrifugal separation, precipitating the acids in a form of their salts, and separating the precipitates from` the extract, the albuminous matter and pectin being coagulated by adding an astringent from the class'consisting of alum, iron chloride and sumac tothe extract prior tothe stage of centrifugal separation preceding precipitation of said salts.

8. In a process for recovering the organic acids and other valuable constituents of tobacco present as solutes in anextract obtained from denicotinized tobacco, albuminous matter and pectin being present in the extract asinsoluble material, the steps of removing the albuminous matter and `pectin by subjecting the' extract to successive stages of .high speed centrifugal separation, precipitating the `acids'in a form 'of their salts and separating the precipitates from the extract, the extract vbeing concentrated by evaporation and the albuminous matter and pectin being coagulated byadding a neutral astringent to the extract prior to the stage of centrifugal separation preceding precipitation of said salts.

9. In a process 'for recovering the organic acids and other valuable constituents of tobacco present as solutes in` an extract obtained from denicotinized tobacco, albuminous matter and pectin being present in the extract as insoluble material, the steps of removing the albuminous Inatter and pectin by subjecting the extract to successiveA stages of high'speed centrifugal separation, precipitating the acids in a form of their salts, and recovering the remaining solutes of the extract as a still deposit upon distillation of the extract.

10. Ina process for recovering the organic acids and other valuable constituents of tobacco present as solutes in a Water extract obtained from 4denicotinized tobacco, the acids being in Administratrix therform of their dissolved ammonia salts, and albuminous matter and pectin being present in the extract as` insoluble material, the steps of removing the albuminous matter and pectin by subjecting the extract to 'successive stages of high speed centrifugal separation, precipitating the acids in the form of calcium salts and separating the precipitates from the extract.

11. In a process for recovering the organic acids and other valuable constituents of tobacco present as solutes in a water extract obtained from denicotinized tobacco, the acids being in the form of their dissolved ammonia salts, and albuminous matter and pectin being present in the extract as insoluble material, the steps of removing the albuminous matter and pectin by subjecting the extract to successive stages of high speed centrifugal separation, precipitating the acids in the form of calcium salts and separating the precipitates from the extract, the albuminous matter l and pectin being coagulated by adding an astringent from the class consisting of alum, iron chloride and sumac to the extract prior to the stage of centrifugal separation preceding precipitation of said salts.

l2. In a process for recovering the organic acids and other valuable constituents of tobacco present as solutes in a Water extract obtained from denicotinized tobacco, the acids being in the form of their dissolved ammonia saltsf, and albuminous matter and pectin being present in the extract as insoluble vmaterial, the steps of removing the albuminous matter and pectin by subjecting theextract to successive stages of high speed centrifugal separation, precipitating the yacids in the form of calcium salts and recovering the remainingl solutes of the extract as a still deposit upon distillation `of the extract.

13. In a process for recovering the organic acids and other valuable` constituents of tobacco present as solutes in a Water extract obtained from denicotinized tobacco, the acids being in the form of their dissolved ammonia salts, and albuminous matter and pectin being present in the extract as insoluble material, the steps of subjecting the extract to high speed centrifugal separation, evaporating the extract to concentrate it, coagulating the albuminous matter and pectin by adding a neutral astringent to the extract, again subjecting the .extract to high speed centrifugal separation, adding calcium chloride and alcohol to the extract to precipitate the salts of said acids and recovering the solutes remaining in the extract as a still'deposit upon distillation of the extract.

yJENNE CAMPBELL RADER, for the Estate of Lyell M. Rader, .Deceasedv Ii D 

